Trends in incidence, prevalence, and mortality of neuromuscular disease in Ontario, Canada: A population-based retrospective cohort study (2003-2014)

BACKGROUND: Population trends of disease prevalence and incidence over time measure burden of disease and inform healthcare planning. Neuromuscular disorders (NMD) affect muscle and nerve function with varying degrees of severity and disease progression. OBJECTIVE: Using health administrative databases we described trends in incidence, prevalence, and mortality of adults and children with NMD. We also explored place of death and use of palliative care. METHODS: Population-based (Ontario, Canada) cohort study (2003 to 2014) of adults and children with NMD identified using International Classification of Disease and health insurance billing codes within administrative health databases. RESULTS: Adult disease prevalence increased on average per year by 8% (95% confidence interval (CI) 6% to 10%, P <.001), with the largest increase in adults18-39 years. Childhood disease prevalence increased by 10% (95% CI 8% to 11%, P <.0001) per year, with the largest increase in children 0 to 5 years. Prevalence increased across all diagnoses except amyotrophic lateral sclerosis and spinal muscular atrophy for adults and all diagnoses for children. Adult incidence decreased by 3% (95% CI -4% to -2%, P <.0001) but incidence remained stable in children. Death occurred in 34,336 (18.5%) adults; 21,236 (61.8%) of whom received palliative care. Death occurred in 1,009 (5.6%) children; 507 (50.2%) of whom received palliative care. Mortality decreased over time in adults (odds ratio (OR) 0.86, 95% CI 0.86–0.87, P <.0001) and children (OR 0.79, 95% CI 0.76–0.82, P <.0001). Use of palliative care over time increased for adults (OR 1.18, 95% CI 1.09 to 1.28, P <.0001) and children (OR 1.22, 95% CI 1.20 to 1.23, P <.0001). CONCLUSIONS: In both adults and children, NMD prevalence is rising and mortality rates are declining. In adults incidence is decreasing while in children it remains stable. This confirms on a population-based level the increased survival of children and adults with NMD.